Trojan.GenericKD.3016333

This malware is distributed via a spam email message that pretends to be a notification from either the POSTNORD or AUPOST postal services (POSTNORD caters to Denmark and Sweden, while AUPOST deals with delivery in Australia). The text content of the message is typically about lost or undelivered packages and the email includes a contain ZIP file attachment that is the actual ransomware file. Malicious links in the email text content reportedly could also lead the user into downloading the ransomware file.

The ZIP file attachment most commonly uses the filenames "postnord_info_59278.exe", "bolletta_36135.exe", and "AUPOST_info_23884.exe". The attachment contains an executable program that uses a PDF file icon; this is a common technique used by malware authors to trick users into thinking that the file is a document rather than an executable program.

Ransomware executable file disguised as a PDF document

If the camouflaged executable file is run, it injects inject malicious code into the "explorer.exe" processes. It moves the ransomware file to %WINDOWS% and renames it as <8_random_alphanumeric_characters>.exe.

It then removes other copies in %LOCAL_APPDATA%\temp\ and encrypts the user's files. It also drops a text file containing the following ransom demand, as well as instructions for payment:

=============================================================================== !!! Vi har krypterat dina filer med Crypt0L0cker virus !!! =============================================================================== Dina viktiga filer (inklusive de p ntverksdiskar, USB, etc): bilder, videor, var dokument krypteras med vr Crypt0L0cker virus. Det enda sttet att f dina filer tillbaka r att betala oss. Annars kommer dina filer att g frlorade.Klicka hr fr att betala fr filer tervinning: ------------------------------------------------------------------------------- ------------------------------------------------------------------------------- [=] Vad har hnt med mina filer?Dina viktiga filer: bilder, video, var dokument krypteras med vr Crypt0L0cker virus. Detta virus anvnder mycket stark krypteringsalgoritm - RSA-2048. Brytning av RSA-2048 krypteringsalgoritm r omjlig utan srskild krypteringsnyckel. [=] Hur kan jag f mina filer tillbaka?Dina filer r nu oanvndbara och olslig, du kan verifiera det genom att frska ppna dem. Det enda sttet att terstlla dem till ett normalt tillstnd r att anvnda vr speciella dekryptering programvara. Du kan kpa denna dekryptering programvara p vr hemsida [malware_site]. [=] Vad ska jag gra hrnst?Du br beska vr hemsida [malware_site] och kpa dekryptering fr din dator. [=] Jag kan inte komma till din webbp

The malware also uses a domain generation algorithm that based on its network activity; the generated domains are used by the malware to determine the location of its command and control (C&C) server, which it will later try to contact. Generated domains are:

• nwowapi.ksmvryodp.com
• akimhsewf.ksmvryodp.com
• hkyjymubudy.ksmvryodp.com
• wsyhew.ksmvryodp.com
• ipokikgzadg.ksmvryodp.com
• izvli.ksmvryodp.com
• acujyz.ksmvryodp.com
• erojibpfi.rygzatyee.com
• aqyn.rygzatyee.com
• ahuby.rygzatyee.com
• orid.rygzatyee.com
• eqova.rygzatyee.com
• eqilufyk.rygzatyee.com
• afazoriju.rygzatyee.com

The presence of the malware's randomly named file in the %WINDOWS% folder is an indicator of infection; another such indicator is the existence of the ransom note and instructions for payment. The malware also creates the following autorun keys, mutexes and component files, which are also indicators of infection:

• Autorun keys:
• Mutexes:
• Component files: